14 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 





 may be considered the result of the first effort to determine 

 the synodic period of rotation of the sun, by the help of the 

 magnetic needle. The true period of the rotation of the sun 

 would hence appear to be about 24.55 days, very closely co- 

 inciding with the value obtained from astronomical observa- 

 tions from the period of rotation of the spots on the equato- 

 rial zone of the sun (according to Sporer, 24.041 days). 19 (7, 



xxxv., September 2, 284. 



______ m 



TRANSIT OF VENUS IN 1874. 



The attention of astronomers throughout the world is di- 

 rected toward the approaching transit of Venus, to occur on 

 the 18th of December, 1874, and it is hoped that the United 

 States Congress, with the same liberality that induced it to 

 make an appropriation for the observation of the solar eclipse 

 of December last, and for the polar explorations under Cap- 

 tain Hall, will also, at the proper time, advance the funds 

 necessary for the research in this ease. The British, German, 

 and other foreign governments have already initiated meas- 

 ures looking toward concerted action on the part of Europe- 

 an astronomers in reference to the observation of this phe- 

 nomenon ; and Professor Hall, of the Washington Observato- 

 ry, in a late communication to the Journal of Science, ex- 

 presses the hope that a similar concert of action will be set- 

 tled upon by American astronomers, in order that they may 

 not be behind their European confreres in the attempt to se- 

 cure satisfactory results. A committee has been appointed 

 by the National Academy of Sciences to .take into considera- 

 tion a general plan of operations, and it is expected that a 

 report will be made on the subject at the approaching meet- 

 ing in Washington City. 4 D, April, 307. 



PEIZE FOE TELESCOPIC COMETS. 



The Imperial Academy of Sciences of Vienna has offered a 

 prize of twenty Austrian ducats, or a gold medal of the same t 

 value, for the discovery of not less than eight new telescopic 

 comets prior to the 1st of June, 1872. This is in view of the 

 fact that, whatever the progress made in astronomy general- 

 ly, but little has been added to our knowledge of the comets, 

 and at the present day we can only catalogue two or three 

 hundred out of the many thousands that doubtless belong to 



